OnePlus 3 has 6GB RAM, but even with that it can keep less apps in memory than other smartphones with 3GB or 4GB RAM.
It seems OnePlus 3 isn't able to take full advantage of that 6GB RAM, meaning the memory management here is quite aggressive leading to quick app reloads. But this is by design, atleast that's what OnePlus co-founder Carl Pei says. According to a twitter conversation with a customer, Carl Pei said that they are following a "different strategy" with memory management which increases battery-life. But we are free to modify settings to have more apps in memory.
However, to make changes to memory management you have to root your smartphone. Once done, you can find the Build.prop file in the phone's root directory, now you can edit "ro.sys.fw.bg_apps_limit" or the limit of how many apps can remain open in the background from 20 to 36 or 42. Both work and improve memory management by a huge margin.
Can this have an affect on battery-life? Yes, it can and it may affect performance as well. Moreover, this is a bit too technical for the average user.
So, here's where we are at right now. It doesn't seem OnePlus is going to alter its RAM Management strategy on the OnePlus 3, so if you are being bothered by it, then you can root you phone and make the changes you saw above. Its quite safe to do this, as OnePlus would still honor your warranty even if the device is rooted.
